Plier-type tools for gripping or holding a workpiece generally have two jaws mounted on shanks which are pivotally interconnected for relative swinging motion.
In order to exert a firm grip on an engaged workpiece, it is desirable to provide each jaw of such a tool with a multiplicity of engagement faces. A particularly advantageous jaw structure comprises a base provided with workpiece-gripping webs rising from a base, these webs having parallel major faces enabling them to slide into gaps between corresponding webs on another such jaw. The webs may have workpiece-engaging faces transverse to their major faces which are alternately inclined in opposite directions with reference to a midplane bisecting these major faces, thereby forming a V-shaped trough for the workpiece; as the two jaws interengage with their webs interleaved, the workpiece is squeezed in a contracting channel formed by their confronting troughs.
Such a jaw structure, known for well over fifty years (e.g. from German patent No. 340,581), requires a precise alignment of the webs of each jaw with the gaps of the opposite jaw to insure proper interfitting if the gap width only slightly exceeds the web thickness, as is obviously necessary if undesirable deformations of the workpiece are to be avoided. Thus, the prior art has used such jaws only with parallel motion in a vise-type appliance or in pliers provided with means for rectilinear guidance, as in the aforementioned German patent, or else with major web faces perpendicular to the pivotal axis as shown in Swiss patent No. 80,554.